This invention relates to a novel therapeutic leg elevator for use following surgery. More specifically, this invention relates to a therapeutic leg elevator for use in promoting venous flow during post-operative patient recuperation.
Subsequent to leg or hip surgery, a patient is usually confined to a bed in a recuperative supine position. During such recovery, swelling and the absence of muscle contractions, etc. tends to inhibit the return flow of blood from the lower extremities of the leg. For example, surgery performed upon the knee complicates return to the heart of blood from the foot. The accumulation of excess fluid, known as edema, in the foot is a result of a higher osmotic pressure in the tissues surrounding the veins than in the veins themselves. Obstruction to tibial venous flow, for example adjacent the knee, results in edema by the mechanical factor of increased pressure in the capillaries of the foot. The excess fluid causes additional swelling, which is uncomfortable for the patient, and may lead to another undesirable condition known as venous stasis. The slowing of circulation of the blood, or venous stasis, may lead to venous thrombosis. Venous thrombosis may result in vein occlusion and possible pulmonary emboli, or clots to the lung, which are potentially fatal. Inhibition of circulation also tends to retard convalescence of the operative portion of the leg or hip.
It is therefore highly desirable to promote and facilitate venous outflow from the lower extremities of the leg. This may be accomplished by physical, versus prescriptive, means. Two physical means by which venous outflow can be enhanced are exercise and elevation of the lower extremity of the leg above the heart. During exercise, the calf muscle reduces venous pressure in the deep veins by emptying them and when the muscle relaxes, the superficial veins drain into the deep system rapidly. The ability to move large volumes of blood during the hyperemia of exercise prevents edema formation by maintaining a normal pressure gradient across the capillary bed. When the leg is elevated above the heart, gravity induces blood to flow away from the foot and back to the heart.
One previously known leg rest supported a patient's leg under the calf and allowed the foot to extend beyond the support. The leg rest did not, however, elevate the foot above the knee, and the potential for edema in the foot remained.
This simple configuration was then modified to include an arcuate depression in a gently sloping surface of an elevator which cradled and elevated the leg. However, the foot was still allowed to drape over the end of the elevator, contributing to problems of the type previously described.
An improved technique for elevating the leg was devised in which there were two different inclines In this configuration, the foot was elevated above the knee, and the knee was elevated above the hip. This improved the passive return of blood flow to the heart by gravity and decreased incidence of edema. Also, units have been devised in the past in which the angles of elevation could be altered for the needs of individual patients.
In yet another configuration, a heel supporting boot encompassed the lower leg from the foot to the calf and used straps across an uncovered portion of the lower leg to secure the support to the leg. The foot was in contact with the support and only the toes were exposed. This configuration did not have differentially sloping inclines; it elevated the foot relative to the knee.
An alternative arrangement to the configurations previously described is sometimes employed whereby pillows elevate the patient's knee, and multiple pillows are utilized to elevate the foot further. This arrangement, however, is not particularly stable and the pillows must be manipulated until a comfortable arrangement is found.
Passive compression has been applied to the leg by putting pneumatic tourniquets around the leg and having the tourniquets squeeze the leg to induce circulation. The action is such that by compressing the veins, blood is forced to circulate. Check valve like mechanism within the veins control the direction of blood movement so that movement in the wrong direction is not a concern. The disadvantage to using a tourniquet is that the patient must be monitored and cannot self control the frequency of compression.
The difficulties suggested in the preceding are not intended to be exhaustive but rather are among many which may tend to reduce the effectiveness of prior therapeutic post surgery leg elevators. Other noteworthy problems may also exist; however, those presented above should be sufficient to demonstrate that therapeutic leg elevators appearing in the past will admit to worthwhile improvement.